Expanding the wildlife reservoir landscape: A high-throughput molecular surveillance study of zoonotic pathogens in Korean water deer

The movement of wildlife across geographic boundaries increasingly drives the emergence and dissemination of transboundary zoonotic diseases. Here, we applied the TaqMan Array Card (TAC) platform for the first time in wildlife disease surveillance, enabling high-throughput screening of multiple pathogens in Korean water deer (<i>Hydropotes inermis argyropus,</i> KWD)-a species widely distributed and frequently interacting with humans and livestock. Between April and November 2023, we collected 192 spleen tissue samples from 12 regions. Pathogen screening was performed using the TAC system, with positive detections subsequently validated via phylogenetic analysis. Seven zoonotic pathogens were identified: <i>Ehrlichia canis</i> (0.5 %), <i>E. muris</i> (1.6 %), <i>Neoehrlichia mikurensis</i> (4.2 %), <i>Candidatus</i> Rickettsia longicornii (26.0 %), <i>Rickettsia raoultii</i> (2.1 %), <i>Bartonella schoenbuchensis</i> (6.8 %), and <i>Giardia duodenalis</i> (1.0 %). Notably, <i>E. muris</i> was detected in KWD for the first time globally, and <i>G. duodenalis</i> was identified in spleen tissue-marking the first such report from any cervid species. Spatial and temporal analyses revealed distinct region-specific and seasonal trends in pathogen prevalence, providing key epidemiological insights. These results underscore the ecological significance of KWD as potential reservoirs and amplifiers of emerging zoonoses. Furthermore, the study demonstrates the utility of the TAC system as a rapid, scalable diagnostic platform for wildlife pathogen surveillance, supporting proactive disease monitoring under the One Health framework.